Rocking hearth furnace

ABSTRACT

A hearth in a heat processing furnace has a plurality of angularly disposed baffles arranged in alternating overlapping relationship extending longitudinally on the upper surface thereof. The hearth is mounted for oscillating movement about a longitudinal axis so that periodic rocking of the hearth will advance articles along its upper surface by the sliding or rolling of the articles back and forth between alternate baffles.

M lMarch 20, 1973 ilnited States Patent 1191 Jarema [5 1 ROCKING HEARTHFURNACE 1,799,956 5 1931 Cope..1...1...........................263/2lC[75] Inventor: Alexander J. Jaremakiver Forest 2,916,276 12/1959Coneetal......................... ...263/6R Primary ExaminerJohn J.Camby Att0meySmythe & Moore [73] Assignee: Solar Basic Industries Inc.,Milwau- [57] ABSTRACT A hearth in a heat processing furnace has aplurality of angularly disposed baffles arranged in alternating kee,Wis.

[22] Filed: April 15, 1971 [21] Appl.No.: 134,225

overlapping relationship extending longitudinally on the upper surfacethereof. The hearth is mounted for oscillating movement about alongitudinal axis so that [52]U.S.Cl...............................198/2l8,432/l34 eriodic rocking ofthe hearth will advance articles 0. MC /1 2 b1 R FM 3 6 m .mh "C r a e"S 1 m d t d l ME .1] 00 55 ll along its upper surface by the sliding orrolling of the articles back and forth between alternate baffles.

[56] References Cited UNITED STATES PATENTS 5 Claims, 8 Drawing Figures1,405,762 2/1922 Curtis.................................263/2lCPATENTEDmzom "3 1, 34

SHEET 2 [IF 2 INVENTOR ALEXANDER J. JAREMA ATTORNEY 5' ROCKING HEARTHFURNACE A heat processing furnace adapted for continuous operation isprovided with a form of a conveyor for advancing the articles to betreated through the furnace. One such form of structure essentiallycomprises a hearth upon which the articles are supported as they aresubjected to heatingfrom electric heating elements or burners disposedadjacent the hearth. A conveyor is then employed to move the articlesalong the hearth so that each article is exposed to the heat source fora predetermined duration of time. It has been proposed in the past toprovide such a furnace with a reciprocating hearth which advances thearticles as it supports the articles during the heating process. Othersuch furnaces have been provided with shaking or vibrating hearths whichalso function to advance the articles being supported thereon.

One of the objects of the present invention is to provide an improvedconveyor heat processing furnace.

Another of the objects of the present invention is to provide a heatprocessing furnace through which articles upon a hearth are advanced byperiodic rocking of the hearth.

Another object of the present invention is to provide a conveyor heattreating furnace which is particularly adapted to ultra-high temperatureprocessing.

According to one aspect of the present invention, a heat processingfurnace may comprise a hearth therein and means for oscillating thehearth. A plurality of an-' gularly disposed baffles are arranged inalternating overlapping relationship on the upper surface of the hearthalong a direction parallel to the axis of oscillation. Rocking oroscillating of the hearth about the axis of oscillation will cause thearticles to roll or slide back and forth between alternate baffles sothat the articles are positively and uniformly advanced along the hearthin a direction parallel to the axis of oscillation.

The baffles are angled toward the entrance or supply end of the hearthwith their inner ends overlapping each other and their outer endsbounded by longitudinally extending retaining lips or walls.

A second set of similarly disposed baffles may be positioned adjacentthe first set of baffles but angled in the opposite direction so as todefine a direction of advance of the articles which is counterflow tothe firs direction of movement.

Other objects, advantages and features of the present invention willbecomeapparent from the accompany ing description and drawings, whichare merely exemplary.

In the drawings:

FIG. 1 is a vertical sectional view taken through the longitudinal axisof a heat processing furnace incorporating the present invention;

FIG. 2 is an end elevational sectional view of the furnace shown in FIG.1;

FIG. 3 is a sectional view taken along the line 3-3 of FIG. 2 andshowing the upper surface of the hearth in plan view;

FIGS. 4A and 4B are fragmentary top and end views of the hearth whenrocked in one direction;

FIGS. 5A and 5B are similar to FIGS. 4A and 4B when the hearth is rockedin the opposite direction; and

FIG. 6 is a top plan view of a modification of the hearth of the presentinvention.

Proceeding next to the drawings wherein like reference symbols indicatethe same parts throughout the various views, a specific embodiment ofthe present invention will be described in detail.

FIG. 1 illustrates generally at 10 a heat processing furnace accordingto the present invention which is provided with a passage 11therethrough passing through a chamber 12 in which are mounted aplurality of heating elements 13 which may be electric or also may begas or oil burners.

A hearth 14 having an upper surface 15 is mounted for oscillatorymovement about a longitudinal axis 16 by means of shafts l7 and 17ajoumaled in bearing blocks 18 and 18a. The shaft 17 is connected to avariable speed tilting or oscillating mechanism which is not shown inthe drawings.

The upper surface 15 of the hearth is provided with a plurality ofangularly disposed baffles 20 which are arranged in alternatingoverlapping relationship along a direction parallel to the axis ofoscillation as may be best seen in FIG. 3. The baffles 20 form asubstantially herringbone pattern with their inner ends 21 extendingbeyond the central axis of the upper surface of the hearth. The centralaxis in this embodiment is positioned in the same vertical plane as theoscillatory axis 16 when the hearth is in its horizontal position.

The outer ends 22 of the baffles abut retainer edges 23 and 24 whichextend longitudinally on the upper surface of the hearth.

One end of the hearth extends outwardly from the furnace to define aloading area as indicated at 25. This area provides a space upon whichthe articles to be heat treated are introduced. A suitable meteringdevice known in the art may be positioned at the front or loading areaof the hearth to regulate the flow of articles being introduced upon thehearth. The meter is preferably of a type which will not overload thefurnace hearth.

At the other or discharged end of the hearth, indicated at 26, there isprovided a receiving pan 27.

The hearth plates or supporting surfaces of the hearth are cast of heatresisting alloy or molded of alumina or other ceramic with the retainingedges and herringbone baffles. At any given moment, the hearth is onlysparsely loaded with articles, with the ultimate rate of feed beingdetermined by the metering device loading the hearth at the front end25. The slow continuous rocking of the hearth causes the articles toalternatively shift from side to side between the alternate baffles. Thearticles are thus advanced at a uniform rate toward the discharge end 26of the hearth.

The articles which can be processed may include but are not limited tosprings, bearing races, chain links, chain saw teeth, concrete drivestuds, nuts, bolts, Allen head wrenches, shoe shanks, textile needles,office machine stampings, and a wide range of similar articles.

The conveying heat processing furnace according to the present inventionis particularly adaptable to ultrahigh temperature applications sincethe supporting structure for the hearth can be positioned outside of thefurnace and, thus, need not be subject to the high temperaturesencountered within the furnace. Further, the mechanism for oscillatingthe hearth to advance the articles to the furnace is also positionedoutwardly from the furnace. Thus, the actual hearth can be molded of anyhigh temperature refractory so that the upper limit of the heatprocessing temperature is defined only by the refractory material of thehearth and furnace and of the heating source.

FIGS. 4A, 4B and 5A, 5B show the path of travel of articles as thehearth is oscillated.

In FIG. 6 there is shown a modification of the present invention whereina second hearth with angularly disposed baffles is positioned adjacentto the first but with the baffles of the second hearth angled in theopposite direction. Thus, the oscillating of the hearths will cause thearticles thereon to be conveyed in a U-shaped path as indicated by thearrow 30. With this arrangement, the articles may be both supplied anddischarged at the same end of the furnace at 31. The other ends of thehearths are provided with a fiat area 32 by means of which the articlesare shifted from one hearth to the other.

It will be understood that changes in various details of constructionand arrangement of parts may be made without departing from the spiritof the invention except as defined in the appended claims.

What is claimed is:

1. In a heat processing furnace, the combination including a hearthwithin the furnace, means for oscillat-' ing said hearth about an axisthereof, a plurality of angularly disposed baffles having their innerends arranged in alternating overlapping relationship on the uppersurface of said hearth along a direction parallel to the axis ofrotation whereby rocking of said hearth causes the articles to travelback and forth between alternate baffles so that the articles areintermittently advanced along the hearth.

2. In a heat processing furnace as claimed in claim 1 and furthercomprising longitudinal retaining means on said hearth upper surfacealong the outer ends of said baffles.

3. In a heat processing furnace as claimed in claim 1 wherein saidbaffles are angled toward the end of the hearth at which articles aresupplied.

4. In a heat processing furnace as claimed in claim 1 wherein the innerends of said baffles extend beyond the center line of the upper surfaceof the hearth.

5. In a heat processing furnace as claimed in claim 1 and comprising asecond hearth similarly disposed and adjacent to the first hearth buthaving baffles angled in the opposite direction to define a seconddirection of movement opposite to the first direction of movement sothat articles are introduced at one end of one hearth, advanced incounterflow fashion, and discharged at the same end of the furnace.

1. In a heat processing furnace, the combination including a hearthwithin the furnace, means for oscillating said hearth about an axisthereof, a plurality of angularly disposed baffles having their innerends arranged in alternating overlapping relationship on the uppersurface of said hearth along a direction parallel to the axis ofrotation whereby rocking of said hearth causes the articles to travelback and forth between alternate baffles so that the articles areintermittently advanced along the hearth.
 2. In a heat processingfurnace as claimed in claim 1 and further comprising longitudinalretaining means on said hearth upper surface along the outer ends ofsaid baffles.
 3. In a heat processing furnace as claimed in claim 1wherein said baffles are angled toward the end of the hearth at whicharticles are supplied.
 4. In a heat processing furnace as claimed inclaim 1 wherein the inner ends of said baffles extend beyond the centerline of the upper surface of the hearth.
 5. In a heat processing furnaceas claimed in claim 1 and comprising a second hearth similarly disposedand adjacent to the first hearth but having baffles angled in theopposite direction to define a second direction of movement opposite tothe first direction of movement so that articles are introduced at oneend of one hearth, advanced in counterflow fashion, and discharged atthe same end of the furnace.